Page 418 - Elements of Chemical Reaction Engineering Ebook

Sec. 7.41 Enzymatic Reaction Fundamentals 389

TABLE E7-7.1 RAW AND PROCESSED DATA
-

0.20 1.08 5.0 0.93
0.02 0.55 50.0 1.82
0.01 0.38 100.0 2.63
0.005 0.20 200.0 5 .OO
0.002 0.09 500.0 11.11

'Z /
I
I4c
-jf ; Lineweaver- Burk plot

/
4
2 -
-
-
- --- 74. Vm**
1
"mx I 1 I I
-
1
CW,,
Figure E7-7.1 Lineweaver-Burk Plot.
From the slope, which is 0.02 s, we can calculate the Michaelis constant, K,:
For enzymatic
reactions the two .- Km = slope = 0.02 s
key rate-law 'ma,
parameters are
V,ax and K, K, = 0.0266 kmol/m3
Substituting K, and V,, into Equation (7-89) gives us
-r, = 1.33 Cure, (E7-7.3)
0.0266 + Cure,
where Cue, has units of kmol/m3 and -r, has units of kmol/m3.s. Levine and
LaCourse suggest that the total concentration of urease, (E,), corresponding to the
value of V,, above is approximately 5 g/dm3.

7.,4.3 Batch Reactor Calculations

A mole balance on urea in the batch reactor gives

dNurea
-=
Mole balance - -rurtxiv
dt